Article View: comp.sys.dec
Article #975Re: Decstation serial port <=> rs232(db25) connection
From: Richard Seymour
Date: Mon, 04 Dec 1989 21:45
Date: Mon, 04 Dec 1989 21:45
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3123 bytes
This is a guess about DEC's adapters, based on their descriptors.
I haven't done this yet, but i'm going to...
You can also do a little check-out with voltmeters.
DTE="terminal or printer" (Data Terminal Equipment) pinout:
on a 25-pin connector that means what-goes-on-the paper arrives
on pin 3. If there's a keyboard, it comes out pin 2 (as viewed
from/at the terminal's connector).
DCE= modem pinout: 2/3 are reversed. (hence the output of the modem
(pin 3) feeds the "input" of the printer (also pin 3)).
My guesses appear as lines without ">" far below...
-- dick
In article <297@edison.UUCP> don@edison.UUCP (Don Kossman) writes:
>In article <804@lclark.UUCP>, dan@lclark.UUCP (Dan Revel) writes:
>> I would like to connect a modem or a terminal to the serial port on
>> a Decstation 3100. How does the RJ-11 jack map to an RS-232 (DB-25)
>> pin configuration?
>
>i'm trying to do the same thing on a vaxstation 3100, which
>i assume has the same (strange) phone-like serial connectors.
>
>what i've found out so far is that the connector is NOT an rj-11, since
>the tab is offset from the centre. DEC will sell you a cable with
>such a connector on either side (they call this an MMP connector).
>part number is BCE16E-xx where xx is 02, 10, 25 or 50. this maps to
>2, 10, 25 or 50 feet. cost is 4$ to 15$. i believe you can get this
>via decdirect.
>
>then you need an MMP to RS232 adaptor. this is where i'm stuck,
>since there are at least 6 and i don't know which is appropriate
>for what. DEC tech support hasn't been able to help, they wanted
>to know which DEC modem or printer i wanted to connect... wouldn't
>talk to me about HP laserjets and hayes modems.
>
>here is the info, such as it is, that i got from the DEC electronic store.
>
> H8571-A 31$ 25-pin passive adapter
--- would probably be proper for a 25-pin modem (female??)
> H8571-B 26$ 9-pin passive adapter
--- would probably be proper for a 9-pin modem
> H8571-C 21$ RS232 male adapter unfiltered
--- would probably be modem pinout, like the -D, but without static filters
> H8571-D 30$ 25-pin adapter - male
--- would probably be like the -C but with static filters in-line
> H8571-E ??? male DTE 25-pin
--- would connect to a terminal or printer (DTE=DataTerminalEquip)
a modem is called DCE (Data Communication Equipment)
> H8571-J $$$ 9-pin serial printer
---- the 9-pin DTE pinout (instead of the -B modem pinout)
Technical Details
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rice!uw-beaver!milton!seymour From: seymour@milton.acs.washington.edu (Richard Seymour) Newsgroups: comp.sys.dec Subject: Re: Decstation serial port <=> rs232(db25) connection Keywords: Decstation serial port Message-ID: <806@milton.acs.washington.edu> Date: 4 Dec 89 21:45:07 GMT References: <804@lclark.UUCP> <297@edison.UUCP> Reply-To: seymour@milton.acs.washington.edu (Richard Seymour) Organization: University of Washington, Seattle Lines: 57